#include using namespace std; typedef long long ll; typedef vector vint; typedef pair pint; typedef vector vpint; #define rep(i,n) for(int i=0;i<(n);i++) #define reps(i,f,n) for(int i=(f);i<(n);i++) #define each(it,v) for(__typeof((v).begin()) it=(v).begin();it!=(v).end();it++) #define all(v) (v).begin(),(v).end() #define pb push_back #define mp make_pair #define fi first #define se second #define chmax(a, b) a = (((a)<(b)) ? (b) : (a)) #define chmin(a, b) a = (((a)>(b)) ? (b) : (a)) const int MOD = 1e9 + 7; const int INF = 1e9; int main(void){ ll n, k; cin >> n >> k; ll l = 1, r = n; while(r - l > 1){ ll mid = (l + r) / 2; ll d = n - mid;//nokori ll cnt = d / (mid + 1); if(k <= cnt) l = mid; //もっとダメージ与える else r = mid; } while(1){ ll d = n - l; ll cnt = d / l; if(cnt >= k) l++; else break; } printf("%lld\n", l); return 0; }